tape measure
so, with the help of christina, i learned how tape measures work…perfectly for my needs. it appears that tape measures are all wound up in the opposite direction of their natural curvature. without all the parts holding them back they would unwind themselves only to rewind themselves the other way (clockwise vs. counter-clockwise).
if i rip off one of the halves of the tape measure i’m thinking i can mount it onto my prototype. all that i need is some way to measure the velocity (or the change and direction) of the tape as it gets pulled in and out. perhaps using some gears with a rotary encoder or 360 degree potentiameter will work. i’d like to get that working this week and start on building a sample selector.